This invention relates to cement handling systems and more particularly to a bulk cement storage system utilizing an improved storage unit.
Originally, after being manufactured, cement was stored in large, low level sheds either loose or in bags. The cement, if stored loose was shoveled from the sheds to a ship or car for transportation, or, if stored in bags, were stacked and carried off. However, environmental conditions proved such storage methods both inefficient and costly since much cement was damaged by environmental conditions. As a result, bulk handling technology developed, utilizing cast concrete cylinders, generally called "silos" to hold the loose cement. These silos were tall and narrow so that the height of the stored cement would provide the force for getting the cement out of the bottom of the silos by convenient mechanical means. With the development of pneumatic conveyors, improved bulk handling techniques resulted. The cement could now be speadily transferred from ships to storage sites and from storage sites to transportation means such as trains or trucks. However, the silos were still utilized for the storage of the cement.
Bulk transport of cement is generally carried out by means of covered hopper cars at plants which have the availability of a railroad siding. At locations generally removed from railroad lines, pneumatic truck trailers are utilized. The pneumatic conveyors bring and remove the cement to these cars and trucks. Furthermore, pneumatic conveyors have played an important role in the development of the marine distribution of cement. Many bulk handling ships are virtually self unloading. The cement is stored in the floors of the holds of the ship and the cement is extracted and transferred to a dockside storage facility which is then utilized to distribute the cement to the various locations.
The use of bulk handling technology for cement has provided both time and cost savings. Further advantages of the bulk storage and handling of cement include the avoidance of broken bags of cement, the necessity to provide dry storage areas, as well as permitting the use of bulk distribution to batch manufacturing sites.
Despite the development of bulk handling technology, as well as the pneumatic conveyor systems, the installation of a cement storage and distribution center has been extremely costly and required a great amount of time to construct the distribution center. A basic reason for this cost is that the cement is stored in series of silos. The silo construction generally takes years and is very expensive. A typical cylindrical silo unit is about 10 meters in diameter and can be as high as 50 meters. The cement is fed into the storage silos and retained therein until distribution is needed. Because of the poor flow characteristics of the cement, the silos are typically very tall and narrow so that a flow of the cement can be obtained by the gravitational force on the column of cement which pushes it downward. The cement can then be removed at the bottom of the silo by means of a screw mechanism or a solid fuel pump. The powdered cement when stacked to such a great height in the silo tends to transfer its weight to the walls of the silo container as well as to the base of the silo. Because of the great height, it is necessary that the walls of the silo be very thick and strong throughout the full height of the storage container. This causes the silos to be very expensive in construction and necessitates great amounts of time to build these distribution centers.
It is accordingly an object of the present invention to avoid the aforementioned problems of prior art devices. A further object of the present invention is to provide a bulk cement storage system which can be constructed at reduced cost and shorter periods of time.
Yet a further object of the present invention is to provide a bulk cement storage system which utilizes a storage unit that does not require very thick, strong, weight bearing walls.
A further object of the present invention is to provide a bulk cement storage system which permits the storage of cement in a free standing pile and is covered by a protective dome of light weight construction.
These and other objects, features and advantages of the invention will, in part, be pointed out with particularity, and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawings, which form an integral part thereof.